Torpedo tube



Patented F eb. 29, 1944 TORPEDO TUBE Stuart Netherwood .Barker andGeorge Sidney Selman, Hythe, England, assignors to Hubert Scott-Paine,Hythe, Southampton, England- Application February 15, 1941, Serial No.379,052 I In Great Britain Octoberlt); 1939 2 Claims.

This application corresponds to the application of Stuart NetherwoodBarker and George Sidney Selman, Serial No. 27,631/39, which was filedin Great Britain on October 10, 1939.

This invention is concerned with torpedo-tubes of the kind in which apropellent charge is ignited in a separate combustion chamber, and theproducts of combustion are transferred to the torpedotube through arestricted orifice which ensures a sufliciently high pressure beingmaintained in the combustion chamber, as is necessary for effectivecombustion of the propellent, whilst also ensuring that the pressuredeveloped in the torpedo tube does not rise above the comparatively lowpressure required for discharging the torpedo. It is known in suchtorpedo-tubes to provide an expanding nozzle between the combustionchamber and the torpedo tube, with the smallest area of the nozzle atits point of connection with the combustion chamber, and to protect thisorifice against choking by means of a screen mounted over it. The screenis constituted by a stout circular plate perforated with a large numberof holes; the screen is located centrally over the outlet orifice and isconsiderably larger. For example, the orifice in the combustion chambermay be about /2" in diameter and the screen, say, 6" in diameter.

We have found that such an apparatus leads to irregularities in thefiring, and according to the present invention the restricted orifice isnot in direct communication with the interior of the combustion chamber.

According to the present invention, the conduit, through which theexpanding gases are conveyed from the combustion chamber into thetorpedo tube, comprises a tubular member shaped internally as aconverging and then diverging passage between which is a constrictedthroat; and arranged transversely across but spaced from the entranceend of this conduit is a plate provided with a plurality of holesdirected toward the constricted throat of said tubular member. Thisconstruction and arrangement of parts diminishes the tendency toturbulent flow of the gases from the combustion chamber into the torpedotube.

In the drawing, Fig. 1 is a central sectional elevation of aconstruction embodying the invention; and Fig. 2 is a similar centralsectional elevation of another embodiment of the invention. Likereference characters indicate like parts in these figures.

Referring first to Figure l, the reference H1 indicates a part of thewall of a combustion chamber within which a propellent charge isignited, and the reference I l indicates the torpedo-tube to which thegases are transferred for the purpose of discharging the torpedo. Theconnection between these two parts is effected through a casting [2provided with flanges 13, M to abut the combustion chamber andtorpedo-tube, respectively, and with a central passage I5 through it. Itis also provided With suitable strengthening ribs 2!. This part issecured in any convenient manner to the combustion chamber andtorpedotube, respectively. Within the central passage 15 there ismounted a tube or liner l6 which is shaped internally as aconverging-diverging passage having its constricted throat or smallestcross-sectional area at N. This constricted throat I! receives gasesfrom the interior of the combustion chamber through a rapidly convergingpassage it, and the gases pass to the interior of the torpedo-tubethrough a more gradually diverging passage l9. If the part It extendsonly part of the way through the member l2, as in the example shown, theoutlet end 20 of the passage I5 is shaped to continue the smoothstreamlined form of the passage through the liner It.

In a specific example of a pressure-reducing nozzle according to thepresent invention, we have found, in one instance, that a suitable areafor the throat I! is from 0.4 to 0.5" in diameter.

This throat is formed about 1%" from the inlet end l8, which is about2.5 in diameter. The outlet end is about 3%" from the throat I! and isabout 2.9 in diameter. This member was used with a combustion chamber inwhich a cordite charge was burnt, giving a pressure of 800 to 1200 lbs.per square inch, and the pressure in the torpedo-tube was about lbs. persquare inch. It will be understood, however, that these dimensions aregiven merely by way of example,

since they will need to be varied according to the weight of propellentwhich is used and the pressures which are required in the combustionchamber and in the torpedo-tube, respectively.

At the upper end of the part l6, where it communicates with the interiorof the combustion chamber Iii, there is provided a screen which isformed as a cylindrical member 22 screwed to the upper end of the pipeI6, the end-plate of this cylindrical member being perforated with alarge number of holes 2 1 which are directed toward the constrictedthroat ll; thereby providing an adequate area for the passage of thegases through them, but efiectively prevent the entry of any solidproducts of combustion to the restricted orifice or throat I! whichwould choke it, and reducing the tendency to turbulent flow of thegases. This screen is made of mild steel and to prevent or reducecorrosion, it is heavily dull nickel plated.

In the modified construction shown in Figure 2, the end wall of thecylinder 22 which constitutes the screen is domed to an a propriateradius about a centre which lies at or near the throat I], and theapertures 25 are formed normal to the surface so as to lie approximatelyin the direction of flow of the gases toward the constrictedthroat [1.

We claim:

1. In combination with a tube adapted to contain a torpedo, a combustionchamber secured to said tube and adapted to contain a combustible chargewhich when ignited produces gases for propelling a. torpedo from saidtube, a conduit through which the said gases are conveyed from tube isdiminished.

2. The combination according to claim 1 in which the plate is domed toan approximate radius about a centre which lies near the constrictedthroat.

STUART NETHERWOOD BARKER. GEORGE SIDNEY SELMAN.

